Examination of the kinetics and distribution of viral gene expression by flow cytometry showed that ARP2 knockdown had no or only minor effects on the efficiency of infection and viral gene expression during the first 24 hr following inoculation (which approximately spans the time from the initiation of infection to the time when virus production has become robust) but thereafter ARP2 knockdown reduced the number of infected A549 cells without affecting the magnitude of gene expression per cell. Here, ACTR2 is linked to infection.